This invention relates to exercise equipment, and particularly to a machine for exercising the muscles and practicing the skills that are used in rowing.
Rowing exercise machines are becoming very popular and commonplace. Most rowing machines use pneumatic cylinders to provide the resistance to a rowing stroke. The user sits upon a seat that slides back and forth along a rail, anchors his feet, and moves handles attached to the cylinder or cylinders. This type of rowing exercise machine provides a poor imitation of the actual body movements and muscle development that is needed for competitive rowing.
The standard against which all other rowing exercise machines have been measured is a machine of the type disclosed in U.S. Pat. No. 4,396,188 issued Aug. 2, 1983 to Dreissigacker, et al. In that device, a large flywheel having a plurality of fan-like blades is rotated as the user pulls on a chain attached to a handle. The user exercises against the resistance of the blades moving rapidly through the air, and work is also done in accelerating the flywheel. The wheel is mounted on a drive shaft that also mounts a one-way clutch with a sprocket engaged by the chain. The wheel can thereby rotate freely when the chain is retracted toward the wheel in preparation for the next pulling stroke.
Another recent addition to rowing exercise machines employs a drive wheel which is rotated by a nylon strap pulled by the rower. The drive wheel is connected by a belt to an alternator. The rower works to create an electrical current that is largely dissipated in a power resistor. However, during a stroke the resistence will decline noticeably apparently because the speed of the drive wheel will have increased to the point where armature reaction overcomes the resisting forces.
This same phenomenon of decreasing resistence after the flywheel speed has reached a particular level is associated with eddy-current brakes which have been used to provide resistance in bicycle exercise machines. The phenomenon has not proven to be a problem in such machines because the speed of the bicycle wheel typically never approaches the critical level. The phenomenon has, however, pointed away from the use of eddy-current brakes to provide the resistance in a rowing machine because of the need for a much higher flywheel speed in such machines.
I have developed a rowing exercise machine that provides a move nearly true simulation of the resistances encountered in rowing than any of the approaches previously. At the same time, the rowing exerciser is compact, portable and safe in its operation and construction.